Previously, many types of saliva ejectors have been used in endeavoring to provide an effective means for removing saliva from a patient's mouth during dental treatment.
Previously this device for saliva removal has been limited to screens and the like for separating and isolating matter that is in the mouth created by the type of dental work being completed. Further valves and manually covered holes in the body of the ejector have been used to regulate flow and vacuum from the device and the tip of the ejector is hard and of the same basic material.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however the following U.S. patents are considered related:
______________________________________ U.S. PAT. NO. INVENTOR ISSUED ______________________________________ 5,076,787 Overmyer 31 December 1991 4,221,220 Hansen 9 September 1980 3,453,735 Burt 8 July 1969 1,222,267 Cosad 10 Apri1 1917 602,572 Browne, et al 19 April 1898 ______________________________________
Overmyer in U.S. Pat. No. 5,076,787 discloses a variable suction aspirator head with a solid trap that regulates suction by positioning a slidable outer barrel over a valve tube that contains a number of slotted holes. The device is dissembled for cleaning and sterilization after each use.
U.S. Pat. No. 4,221,220 issued to Hansen teaches a surgical suction nozzle for removing debris from unconscious patients. The suction tip contains a raised ridge inward of the opening in the end. A suction control hole is located in the medial segment of the nozzle allowing control of the amount of suction by placing a finger over the hole during use.
Burt employs a rectangular passage for controlling the amount of suction in the dental aspirator in U.S. Pat. No. 3,453,735. The tip has a two plane surface at different angular relations to the axis of the deflected portion to prevent drawing tissue into the outer end of the tube. The operator places a finger on the passage to obtain the desired negative pressure.
Although the prior art on aspirators has been referred to, it should be pointed out that in dentistry, an aspirator tip and a saliva ejector are two different instruments. The saliva ejector, up until now, being a passage non-operated instrument that usually rests passively in the mouth, drawing away saliva. By contrast, the aspirator tip is an active instrument, which is operated by an assistant while the dentist/oral-surgeon works, and the assistant maintains a clear field of work, by moving the aspirator tip as needed, to areas of debris, such as removal of large amalgam filings, or relatively large amounts of blood, which might otherwise obscure the operating site.
U.S. Pat. No. 1,222,267 of Cosad employs air vents and fluid passages to prevent tissue damage. Two passageways extend almost the length of the device allowing a counter current of air to be passed therethrough. Although a hole is used for airflow, the dental practitioner does not cover the hole in use.
A patent issued before the turn of the century to Browne et al, U.S. Pat. No. 602,522 discloses a glass tube with a strainer and a chamber. The principle of using a tube for ejecting saliva is obviously well known and the tip employs at least two openings one on the end and the other on the side.
As the prior art indicated, the use of U-shaped tube with some types of tip is not by itself novel. Also, a hole in the side for manual volume control has been used previously however, only simple strainers have been employed for retaining debris and the tips are not resilient on the ends. Further, the hole or passage in the side has been limited to just an opening not large enough or configured to clean tools or close and change its shape for regulation of volume.